Baste sewing process



Jan. 9, 1968 BONO BASTE SEWING PROCESS Filed Feb. 8, 1965 '2 Sheets-Sheet 1 Jan.- 9, 1968 Filed Feb. 8, 1965 L. BONO BASTE SEWING PROCESS 2 Sheets-Sheet 2 United States Patent 3,362,363 BASTE SEWING PROCESS Luigi Bono, Pavia, Italy, assignor to Necchi Societa per Azioni, Pavia, Italy Filed Feb. 8, 1965, Ser. No. 431,004 Claims priority, application Italy, Feb. 13, 1964, 3,254/64, Patent 729,373 4 Claims. (Cl. 112-158) ABSTRACT OF THE DISCLOSURE A method for baste stitching a fabric with a conventional home sewing machine which is adapted to sew a zig-zag pattern, comprising alternately shifting the needle bar from one side to the other of a central sewing axis while a fabric moves along said axis and sewing stitches in the fabric only while the needle bar is on one side of the axis but not while it is on the other side.

The present invention is directed to a process for forming basting stitches upon textile material through the use of a conventional, home Zig-Zag type of sewing machine and a means for adapting such a machine in order to carry out said process.

In the field of home type sewing machines, devices are already known which, when desired, are applied to the material presser bar and are actuated by the reciprocating motion of the needle bar. In said devices, the coupling of the stitch is intermittently avoided or skipped, in accordance with a certain sequence, by means of an oscillating member whose movement acts to pull upon the upper sewing thread thereby unlooping the upper thread loop before the gripping point of the rotating hook enters said loop in order to couple it with the lower thread.

In this manner there are formed long stitches, adapted to unite the sewed pieces of material, but easily unseamable.

The above mentioned known devices possess a certain degree of complexity and require a relatively large number of parts.

On the other hand, the presently disclosed process requires very simple means to obtain basting stitches with normal or conventional sewing machines. This process is applied to family type sewing machines which are already disposed to perform zig-zag sewing and in which there exists a difference in phase of the needle relative to the rotating hook, this phase dilference being referred to the two extreme opposed lateral sewing positions relative to a central sewing position and the invention is characterized by the fact that the basting stitches are obtained by having the knotting of a stitch occur in only one lateral position of the needle while it is avoided or skipped in the opposite lateral position of the needle. By repeating the cycle whereby the needle bar executes a certain number of rectilinear reciprocating movements while it is in that lateral position in which the knotting is skipped, and whereby it then executes only one of said movements while it is in that opposite lateral position in which the knotting occurs, there results on the textile material a series of stitches having the desired length.

A preferred embodiment of a device which accomplishes the process of this invention comprises a rotating hook, a needle which cooperates with said hook in a known manner to form stitches, a needle bar upon which is fixed said needle, and control means adapted to transmit lateral displacements to said needle bar according to a pro-established sequence, and said device is characterized by the fact that the distance between the middle of the needle eye and the upper extremity of the needle tong (which generally is standard for needles used on home type sewing machines) is slightly less than said 3,362,363 Patented Jan. 9, 1968 standard distance. From this results that the gripping point of the hook encounters the needle above its eye while the needle is in that lateral position in which knotting is intended to occur, and said gripping point encounters the needle below its eye when the needle is in that opposite lateral position in which the knotting is intended to be skipped or avoided.

In the following description the common terms sewing to the left and sewing to the right are referred to the usual position of the machine operator with respect to the sewing machine.

The objects of the present invention generally are:

(1) To provide a process whereby a conventional, home type, zig-zag sewing machine can be used to perform baste stitching;

(2) To provide a simple means for adapting a conventional zig-zag sewing machine to carry out baste stitchmg.

Specific characteristics, objects, and advantages of the present invention will be manifestly clear from the following detailed description which is referred to the attached drawing, in which:

FIGS. 1 and 2 refer to the case of central sewing and schematically represent the relative positions between needle and hook gripping point at the instant in which the needle is at, respectively, its lowest point and at the succeeding instant in which the ascending needle encounters the hook gripping point.

FIGS. 1, 3, and 5 refer to the present invention and schematically represent the phase relationship between sewing needle and rotating gripping hook while the needle is at the bottom of its reciprocatory stroke and respectively for central line sewing, sewing to the right, and sewing to the left.

FIGS. 2, 4, and 6 schematically represent the situation which prevails respectively for the elements of FIGS. 1, 3, and 5 but subsequently in time, that is, while the needle is ascending and at the moment when the hook engages said needle.

FIGURE 7 is a schematic representation of a normal zig-zag stitch pattern;

FIGURE 8 is a schematic representation of a baste stitch pattern derived from applying the process of this invention to the stitch pattern shown in FIGURE 7;

FIGURE 9 is a schematic representation of another stitch pattern obtained through use of a conventional automatic sewing machine;

FIGURE 10 is a schematic representation of a baste stitch pattern derived from applying the process of this invention to the stitch pattern of FIGURE 9; and

FIGURE 11 is an actual illustration of the baste stitch shown schematically in FIGURE 10.

In the drawing, 1 indicates the sewing needle, 2 indicates the hook gripping point, 3 indicates the eye of needle 1, and 4 indicates the circular trajectory travelled by thegripping point 2.

The needle 1, which is only schematically represented, includes a distinguishing feature relative to conventional needles used in conventional sewing machines. In fact, the needle 1 is characterized by the fact that the distance between the median point of eye 3 and the top of the needle tong is slightly less than the corresponding distance on conventional needles used in home type sewing machines. As is known, in conventional needles this dis tance is universally standard.

Applying, therefore, the needle of this invention to a conventional zig-zag home type sewing machine, the results are as illustrated in the drawing and as below described.

In FIG. 2, which refers to central sewing, the gripping point 2 encounters the ascending needle eye 3. The formation of the stitch is uncertain at this point because the lower part of the loop outline is located, in this particular situation, at the same height as the gripping point 2. It may occur that either said point enters into the loop or that it passes under said loop, and these two possible occurrences respectively correspond to either the realization or non-realization of a coupling of the two threads for the formation of a stitch.

FIG. 4 refers to the case of right lateral sewing, and

the needle is in advanced phase relative to its position in FIG. 2. The intersection between the point 2 and the needle 1 occurs, in this case, at a position on the needle above the eye 3, whereby the point 2 can definitely enter the loop and couple the two threads to form a stitch.

FIG. 6 refers to the case of left lateral sewing, and the needle is in retarded phase relative to its position in FIG. 2. The point 2, following its circular trajectory, encounters or intersects the needle, which is performing its upward movement, at a position on the needle below the eye 3, whereby the point 2 definitely passes below the loop and thereby fails to couple the two threads together. The difference in the distances, between the median point of the needle eye and the top of the needle tong, for the needle used herein as compared to a standard needle is such as to assure the above described relationship between the point 2 and the needle eye 3 as referred to FIGS. 4 and 6.

From what has been above explained, it is obvious that one should proceed as explained below in order to realize basting stitches with a home type sewing machine of the type heretofore mentioned and which is provided with the special shortened needle of this invention.

By having the needle bar of the machine execute a reciprocating axial movement with the needle in the right lateral position of FIGS. 3 and 4, there results a stitch on the textile material. n the other hand, by subsequently having the needle bar execute reciprocating axial movement with the needle in the left lateral position of FIGS. 5 and 6, the needle will penetrate into the textile material without, however, effecting any stitch. Upon return of the needle bar to the position corresponding to FIGS. 3 and 4, another stitch is effected whose distance from the preceding stitch is dependent upon the number of stitches which have been skipped, i.e., the number of times the needle has been reciprocated in the lateral position of FIGS. 5 and 6.

Stitches may be formed, therefore, having any desired length adapted to temporarily hold two pieces of textile together and to be easily unseamed.

The switching or changing over of the needle bar to position the needle either as shown in FIG. 3 or in FIG. 5, may be controlled or actuated either manually or automatically.

Manual changing over may be effected by maneuvering the appropriate control lever which is already provided in zig-zag sewing machines for laterally displacing the needle to its respective right and left sewing positions. Said lever is connected to the carriage of the needle bar through known linkage means.

Automatic changing over may be effected by means of a control member such as a cam which rotates in fixed phase relative to the reciprocating rectilinear movements of the needle bar. Said cam can be mounted, in machines provided with an automatic sewing device, on the same shaft which carries the cams of the automatic sewing device. In this case, the cam profile assumes the function of the manual control lever which would be used in a manual control means. The sewing cycle is correlated to the cam profile which in turn determines the length of the basting stitch.

It is not considered necessary to illustrate in more detail in the drawing or in this description the aforementioned changing over means for the needle bar, because said means are not in any way different from those which are found on all home type zig-Zag sewing machines, with or without the automatic sewing feature.

The above described embodiment is referred to the use of a special needle having a distinct length which renders it appropriate, when applied to the type of machine herein considered, to effect basting stitches in accordance with the herein disclosed principles. The same result which is obtained through use of a shorter needle could obviously also be obtained by appropriately modifying the phase relationship which exists between the reciprocating axial movements of the needle bar and the rotation of the hook in normal sewing. In fact, means can be provided for adjustably fixing a standard needle on the needle bar in either of two different reciprocal positions: one position being that which corresponds to normal sewing, and the other being that which increases the distance between the needle eye and the rotational axis of the hook, whereby the same situation prevails as does when a special, shorter needle is used.

An analogous result may be obtained by providing means which act upon the connection between the needle bar and the main shaft of the machine to provide two different reciprocal positions of the needle bar. Said positions would be easily interchangeable, and one would correspond to normal sewing while the other would correspond to basting according to the above described principles.

Also, by providing means to change the angular keyed position of the book 2 upon its shaft the phase between hook and needle is easily changed in order to obtain the herein described conditions for the formation of basting stitches.

It is quite clear that these last mentioned alternative methods for providing basting stitches in accordance with the principles of this invention, require means which are more complex relative to the preferred embodiment herein disclosed and illustrated.

FIGURES 7 and 8 schematically show the transition from a normal zig-zag stitching to a ba-ste stitching obtained through utilization of the afore-described process and apparatus. If, in a zig-zag sewing machine which is adapted to sew the pattern of FIGURE 7, the stitch control is set to obtain the maximum length of stitch and if it is provided that no knotting of the stitch occurs in one of the two lateral sewing positions of the needle, there results a straight stitching along the other lateral sewing position wherein the distance between two successive stitches is double that between two successive zig-zag stitches (FIGURE 8).

FIGURES 9 and 10 schematically show the transition from the normal stitching pattern produced by a conventional automatic sewing machine to the baste stitch pattern obtained through application of the process of this invention to this same machine. If, in an ornamental stitch pattern (FIGURE 9) wherein the sewing needle reciprocates at intervals a predetermined plural number of times while along one lateral sewing position and only once while along the other lateral position, the stitch knotting is avoided along said one position but effected only along said other position, there results the baste stitch pattern of FIGURE 10, which is pictorially shown in FIGURE 11.

It is to be understood that all modifications, embodiments, alternatives, etc., which are based upon the principles of this invention, to provide basting stitches, are intended to be covered by the scope of the appended claims.

What is claimed is:

1. A method for sewing basting stitches with a conventional Zig-zag type sewing machine in which there exists a phase difference, in the rotary position of the gripping hook relative to the needle, for each of the two respective right and left laterally opposed sewing positions of said needle, said method comprising the steps of:

(a) providing a phase relationship between said needle and said hook whereby with said needle at one of said laterally opposed positions said hook will intersect said needle at a position on said needle above the needle eye, and with said needle at the opposite said laterally opposed position said hook will intersect said needle at a position below the needle eye;

(b) positioning the needle bar so that said needle is at said one lateral position;

(0) operating the sewing machine with said needle performing only one rectilinear reciprocating movement while at said one lateral position;

(d) changing over the needle bar of the machine to place said needle at said opposite lateral position;

(e) operating the sewing machine with said needle performing at least one rectilinear reciprocating movement; and then (f) repeating steps b, c, d, and e.

2. The method of claim 1, characterized by the fact that said needle performs at least a plurality of said reciprocating movements in step e.

3. A method for baste stitching a fabric with a zigzag sewing machine which comprises a sewing needle mounted on a needle bar, said bar being shiftable to place said needle at opposite lateral sewing positions relative to a central sewing position to provide normal zig-zag sewing, said method comprising the steps of:

(a) shifting said bar to place said needle at one of said lateral sewing positions;

(b) sewing a single stitch at said one position in a fabric While moving said fabric past said needle;

(c) shifting said bar to the other lateral sewing position of said needle;

(d) continuing to move said fabric past said needle at least a distance corresponding to one stitch but Without sewing any stitch in said fabric while said needle is at said other lateral position;

(e) repeating steps a through d.

4. The method of claim 3, wherein said fabric is moved past said needle in step d at least a distance corresponding to a plurality of stitches.

References Cited UNITED STATES PATENTS JORDAN FRANKLIN, Primary Examiner. J. R. BOLER, Assistant Examiner. 

3. A METHOD OF BASTE STITCHING A FABRIC WITH A ZIGZAG SEWING MACHINE WHICH COMPRISES A SEWING NEEDLE MOUNTED ON A NEEDLE BAR, SAID BAR BEING SHIFTABLE TO PLACE SAID NEEDLE AT OPPOSITE LATERAL SEWING POSITIONS RELATIVE TO A CENTRAL SEWING POSITION TO PROVIDE NORMAL ZIG-ZAG SEWING, SAID METHOD COMPRISING THE STEPS OF: (A) SHIFTING SAID BAR TO PLACE SAID NEEDLE AT ONE OF SAID LATERAL SEWING POSITIONS; (B) SEWING A SINGLE STITCH AT SAID ONE POSITION IN A FABRIC WHILE MOVING SAID FABRIC PAST SAID NEEDLE; (C) SHIFTING SAID BAR TO THE OTHER LATERAL SEWING POSITION OF SAID NEEDLE; (D) CONTINUING TO MOVE SAID FABRIC PAST SAID NEEDLE AT LEAST A DISTANCE CORRESPONDING TO ONE STITCH BUT WITHOUT SEWING ANY STITCH IN SAID FABRIC WHILE SAID NEEDLE IS AT SAID OTHER LATERAL POSITION; (E) REPEATING STEPS A THROUGH D. 